Vacuum
The void of space is effectively empty of matter, and this vacuum is perhaps the greatest danger of outer space. A creature introduced to a vacuum immediately begins to suffocate (see Suffocation and Drowning on page 404) and takes 1d6 bludgeoning damage per round (no saving throw). Because a vacuum has no effective temperature, the void of outer space presents no dangers from cold temperatures. A creature retains its body heat for several hours in a vacuum. Sound doesn’t travel in a vacuum.
Decompression occurs when a creature suddenly transitions from a pressurized environment to a vacuum, such as by being flung out of an airlock or being inside a sealed structure that becomes heavily damaged. Such a creature takes 3d6 bludgeoning damage (no saving throw) in addition to any suffocation damage.
Zero Gravity:
Movement in zero gravity (also referred to as zero-g) is not the same as flight. Controlled movement is difficult without some form of propulsion, and creatures without something to push off from often find themselves floating aimlessly. A creature in a zero-gravity environment can’t take move actions to move its speed, crawl, or take a guarded step. If a creature is adjacent to or in the same square as an object (including a wall, floor, or ceiling) or another creature one size category smaller than itself or larger, it can take a move action to push off that object or creature, moving at half its land speed in a direction of its choosing (as appropriate); if that object or creature is movable, it begins moving in the opposite direction at that same speed.
Moving in Zero-G: A creature that moves in a given direction continues to move in that direction at the same speed at the beginning of its turn each round (without taking any action); it must move the full distance unless it is able to change its motion by latching on to an object or creature, pushing off in a new direction, or creating thrust of some kind (all of which are considered move actions). If a creature runs into a solid object during its movement, it must succeed at a DC 20 Acrobatics or Athletics check to safely stop its movement; failure means that creature gains the off-kilter condition (see page 276). If a creature runs into another creature during its movement, both creatures must each attempt a DC 20 Acrobatics or Athletics check to avoid gaining the off-kilter condition. A creature anchored to a solid object (such as by the boot clamps available with most armor) receives a +4 bonus to this check. An off-kilter creature in a zerogravity environment can steady itself as a move action that requires a surface to grab on to or some method of propulsion; alternatively, that creature can throw a single item weighing at least 4 bulk (for Medium creatures; 2 bulk for Small creatures) to reorient itself and remove the offkilter condition.
If provided with sufficient handholds, a creature with a climb speed can move along a wall at full speed, as can any creature that succeeds at a DC 20 Acrobatics or Athletics check. Creatures that fly via methods that require an atmosphere, such as wings or turbofans, can’t use their fly speeds in a vacuum; once they reenter an atmosphere, they can recover and get their bearings within 1d4 rounds, after which they can fly normally. Magical flight and methods of flight that provide their own thrust, such as jump jets (see page 206), are not affected. A character in a zero-gravity environment can lift and carry 10 times her normal amount.
Weapons: Thrown weapons have their range increments multiplied by 10 in zero-g. In addition, all ranged weapons no longer have a maximum number of range increments—their wielders simply continue to accrue penalties the farther away the target is.
